Blood Flow and Pain Crises in People With Sickle Cell Disease

Study Summary

Background: \- Many people with sickle cell disease have repeated episodes of severe pain that lasts for days, requiring hospital care. These episodes, called pain crises, may be caused by changes in blood flow. Researchers want to study blood flow in people with sickle cell disease who are having a pain crisis and compare it with their blood flow after the pain crisis has resolved. They also want to compare these measurements against blood flow in healthy people who do not have sickle cell disease. Objectives: \- To study whether changes in blood flow cause pain crises in people with sickle cell disease. Eligibility: * Individuals at least 18 years of age who have sickle cell disease and are being treated for a pain crisis. * Individuals at least 18 years of age who have sickle cell disease and are not experiencing a pain crisis. * Healthy volunteers matched by age and gender with the participants who have sickle cell disease. Design: * Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected. * Participants having a sickle cell pain crisis will have two visits, one during the crisis and one about 4 weeks after the crisis has resolved. * Participants not having a sickle cell pain crisis will have one or two study visits. Blood samples will be collected during at least one of these visits. * Healthy volunteers will have one or two study visits. Blood samples will be collected during at least one of these visits. * During each visit for all participants, cameras and blood flow monitoring equipment will be used to measure blood flow in the forearm. sickle cell disease.